Heat Treat issue!!!

bpiatt

bpiatt

Joined
Jun 17, 2010
Messages
644
Hey everyone,

You may have seen my other post about attempting my first heat treat on 1095. If you havent, what I did was pre-heat the oven to 1500 degrees, I then put the knife in and let it bake for 15 minutes. I quenched in 1 gallon of Canola Oil and then Immediately tempered twice in a toaster oven at 350 degrees for an hour each time.

When I checked the knife after with a file it was hard. Now I have ground away more material and it seems soft. The edge is not as hard as it needs to be. Is there anything I can do before Christmas to fix this issue? I have access to an acetylene torch, should I just heat the edge and re-quench?


Thanks!!

-Ben
 
How warm did it get when you were grinding it after tampering right at the edge?

-Page
 
maybe you are only filing the scaling and oxidation.
Otherwise I will suggest to heat treat again the blade!
 
Canola oil is WAY to slow for 1095

I use Parks #50 for 1095, water works ok but will tend to destroy blades if your not really careful. Brine is the most effective "cheap" option.

take water and dissolve salt until it will float an uncooked egg. this is what blacksmiths and bladesmiths refer to as "Brine"

it's actually a faster quench medium than plain water but because of the salination it is a less turbulent quench so it tends to be less destructive.
 
bpiatt said:
Hey everyone,

You may have seen my other post about attempting my first heat treat on 1095. If you havent, what I did was pre-heat the oven to 1500 degrees, I then put the knife in and let it bake for 15 minutes. I quenched in 1 gallon of Canola Oil and then Immediately tempered twice in a toaster oven at 350 degrees for an hour each time.

When I checked the knife after with a file it was hard. Now I have ground away more material and it seems soft. The edge is not as hard as it needs to be. Is there anything I can do before Christmas to fix this issue? I have access to an acetylene torch, should I just heat the edge and re-quench?


Thanks!!

-Ben
Click to expand...

You have an oven, taking the huge step backwards to a torch will probably not help with your problem. Aside from the issue at hand your temp is off, 1500F will work but is not optimum, for 1095 drop your oven down to between 1475F and 1485F. If you nailed the soak and quench 1095 tempered at 350F should tear up just about any file. When the hardening is spot on most folks would be floored by how much heat has to be thrown at this steel to drop the Rockwell numbers, if you did things correctly you should still be in excess of 63HRC.

If your oven is reading spot on and your time is correct, your solutions should be there, so we could move on to the quench. Canola should at least harden the edge up into the blade up to around 1/8" in thickness... if it was preheated to around 130F and you have good agitation. Check these variables and move on to others. Troubleshooting is only possible if you can identify the variables, you got good accounting of them with your oven, downgrading to a heat source that won't give you any idea of temperature or soak time will only put you farther into the abyss.
 
Alright so it much have been my quench method then. I know 100% my oven is dead nuts accurate, its calibrated to government specifications through work. I know 100% that I didnt over heat the knife because I ground it on the belt sander with not gloves and I dunk in water when I feel the slightest Heat. I am going to reheat the knife and quench in salt water. Is it ok to use regular table salt? Is 1 gallon enough water for a knife that is 9in long, 1.5in wide and .240in thick?

Thanks everyone!

-Ben
 
sunshadow said:
How warm did it get when you were grinding it after tampering right at the edge?

-Page
Click to expand...

Hey Page, I am going to be heat treating this knife in the next 2 hours or so. Do you think you could give me a phone call so I can talk to a professional before my second attempt. This is going to be my last opportunity to do it right and finish the knife before Christmas. My number is 1-585-472-2502.

thanks man
 
you can still overheat the edge without enough heat traveling further up to your fingers. When it gets really thin it doesn't take much.
 
I don't know if it has anything to do with your problem, but 15 minutes sounds like a really long soak for 1095.
 
Mitchell Knives said:
I don't know if it has anything to do with your problem, but 15 minutes sounds like a really long soak for 1095.
Click to expand...

I was originally going to do 5 minutes, but then I was told to do between 10-20 minutes, so I chose 15. The blade is .250 thick. How long you think I should soak for?
 
I think 2 gallons would be better. Did you heat the oil? Warm oil cools faster than cold.
Toaster ovens are often hotter than their settings. I would suggest a regular oven and using an oven themometer. It also helps to bury the blade in dry sand to protect against the oven temp flucuations.
 
bpiatt said:
Alright so it much have been my quench method then. I know 100% my oven is dead nuts accurate, its calibrated to government specifications through work. I know 100% that I didnt over heat the knife because I ground it on the belt sander with not gloves and I dunk in water when I feel the slightest Heat. I am going to reheat the knife and quench in salt water. Is it ok to use regular table salt? Is 1 gallon enough water for a knife that is 9in long, 1.5in wide and .240in thick?

Thanks everyone!

-Ben
Click to expand...

Even with my help I am going to make a prediction that your post following the brine quench will be to tell us about the blade you lost to cracking, I sincerely hope and want you to prove me wrong, but that is my prediction.

Here are some tips to help you in making me eat my words- use some rock salt or ice cream salt and dissolve enough for a 9% solution, do not overheat the water but do not go with ice cold either, between 80F and 160F should be fine. Go into the water in a clean quick slicing action and if you are fast enough (good luck) pull the knife out the quench when the blade is still warm enough to dry off almost immediately, and have the tempering oven up to heat and right beside you when you quench. As soon as you can handle the blade comfortably with bare hands get it in the temper.

Let us know how it works.
 
why the heck am i cringing .. its not even my knife... :o

1095 usta give me fits... typically i forge with lower heats toward the end of a finished blade... then go to the normalize cycles.. ... the blades would be very shallow hardening..

till i tried it in water..

slak quench that is... to the count of 2 and out... 3 and back in



50% good
 
Update:
I called him last night to see how it went, the blade didn't harden in oil, so he tried brine and it went ping, he tried a 1/8 inch thick blade in the brine and it hardened and didn't go ping.

-Page
 
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